Jay Leno has shed more than a dozen pounds and the weighty traditions of the “Tonight Show” that would tie his prime-time future to his late-night past.

The desk that's central to any talk show will go mostly unused. There will also be fewer stars hawking their latest movies, TV shows and albums, and instead more comedy when NBC's “The Jay Leno Show” debuts tonight.

But can the newly trim, 59-year-old Leno bring major change to American television with a one-hour show five nights a week?

“I do think this is the kind of bold move that the networks need to make if they're going to hold on to any part of their primacy in the TV world,” says Tim Brooks, author of “The Complete Directory to Prime-time Network and Cable TV Shows.”

A prime-time show airing each weeknight is unique in U.S. television and has the potential to be copied if it's a success. “When something new comes along on TV, it proliferates all over the schedule,” Brooks says.

Leno, at least publicly, won't play along. He dismissed as “hilarious” the notion that he can single-handedly reverse the shrinking fortunes of broadcast television as viewers defect to cable and other distractions.

He also rejects the idea that he's poised to be an innovator, although the car buff is proud of his new Burbank set. With artwork of his vintage cars as decoration, it displays Leno's passion for automobiles. It even has a compact racetrack outside so celebrities can race environmentally friendly cars.

“Meat and potatoes. Good food at sensible prices,” he says of the new show. “That's all it really is. It's not some groundbreaking thing. It's just a comedy show.”

But it is, crucially, also a budget-conscious show. Leno is taking over real estate that would have belonged to a quintet of one-hour dramas that typically cost about $3 million an episode.

“It's all economic. We're here because we can do five shows for less than the price of what it costs to do ‘CSI: Miami’ or a ‘Law & Order,’ ” Leno says. “That's primary. It's No. 1.” And when most of the series that NBC has fielded in recent seasons are both expensive and flops, the logic becomes unassailable, he contends.

There's another parameter that “The Jay Leno Show” respects, according to its host: the audience demand for immediacy, whether in live reality series such as “American Idol” or a comedy show that's taped the day it airs and avoids reruns save for six weeks a year.

That's an unsettling reality for the scripted dramas, which at 10 p.m. are now found only on ABC and CBS (Fox doesn't program the third hour of prime time on its stations).

The changes have also put many screenwriters out of work. Only the increasingly robust cable dramas such as “Mad Men” or “Damages” are hiring.

Actor-comedian Rachael Harris (“The Hangover”), who will be among Leno's comedy correspondents, says she understands that writers are frustrated at seeing so many jobs vanish. But her writer friends, at least, can see it from her perspective.

“They understand that not only is it difficult for writers, but it's difficult for actors,” Harris says. Besides, she adds, there are people who worked on Leno's “Tonight” who are grateful to have a job on his new show — and, according to Leno, those include 22 union scribes.

Besides helping fashion the opening monologue, Leno's team is working on popular fixtures including “Jaywalking,” his person-in-the-street pop quiz, and funny headlines (the sole reason there's still a desk on the set).

A key staple will be taped reports filed by a corps of young comedians, including Harris, D.L. Hughley, Mikey Day, Liz Feldman, Brian Unger and Owen Benjamin. One Harris contribution is “Recessioning It With Rachael,” in which she offers tips like taking a car for a test drive to run errands. Another piece shows Feldman teaching seniors how to tweet.

Leno is also keeping advertiser-favored young adult viewers in mind with singers such as Jay-Z, Rihanna and Kanye West, who are set to perform together on the debut show.

Leno's ratings will probably not be blockbuster no matter how broad his appeal. He was averaging 5.2 million viewers during his last “Tonight” season to claim the No. 1 spot in late-night. But prime-time shows such as CBS' “CSI: Miami” can easily draw 15 million viewers.

Some longtime industry analysts question how much of a splash “The Jay Leno Show” will make, solid ratings or not.

“I don't see it as being that big. I see it as a programming alternative, but I don't see it as reinventing” prime time, says Shari Anne Brill of the ad-buying firm Carat.

NBC intends to stick with the show for “at least a year and, we hope, many years beyond that,” Rick Ludwin, executive vice president for late-night and prime-time series, told reporters in July, declining to provide a ratings benchmark.

As for Leno, he says if the show is a winner, great; if not, he's content to rest on his 17-year “Tonight” laurels.